Indium tin oxide (ITO) is a widely used material as it has the special characteristic of being a transparent conductor. This makes it ideal for thin displays and solar panels, but it is also fragile and expensive, which is why researchers are looking for materials to replace it. Those at MIT have recently created a graphene-based alternative to ITO for use in solar panels, which is the first realization of such technology.
Graphene has multiple special properties, including high conductivity, transparency, and flexibility, but it is also chemically inert, which can be a problem. To be useful as a solar-panel electrode it has to be possible to build semiconducting nanostructures on top of it, but its inertness inhibits this. The solution the MIT researchers developed is to apply polymer coatings to the graphene, so it may bond with zinc oxide nanowires. Above the nanowires the researchers then placed a photoelectric material, and none of these layers disrupt the graphene's properties.
The solar panel the researchers built has a power conversion efficiency of just 4.2%, which is not much compared to the silicon and ITO solar panels currently on the market, but for specialized applications, it should be competitive. Also the materials and manufacturing process are cheaper than those of traditional solar panels, so we may see this technology hit the market yet.